JP2012077269A - Polymeric material molded article, method for producing the same, and mechanical component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymeric material molded article which inhibits entering of a gas such as oxygen or vapor and occurrence of dimensional change and degradation; to provide a method for producing the polymeric material molded article; and to provide a mechanical component having high reliability and long life although at least a part of it comprises a polymeric material.SOLUTION: A resin pulley 10 includes a rolling bearing 11 and a resin portion 12. The resin portion 12 is formed by injection molding of the polymeric material and is integrally attached to the outer peripheral surface of an outer ring 2 of the rolling bearing 11. The surface of the resin portion 12 of such a resin pulley 10 is coated with an organic inorganic composite membrane containing silicon dioxide prepared by converting polysilazane and an acrylic resin and having a gas barrier property.

Description

  The present invention relates to a polymer material molded article formed by molding a polymer material, a method for producing the same, and a machine part at least partially composed of the polymer material.

  The type of resin that is a material of the cage made of resin incorporated in the rolling bearing is determined depending on the operating temperature, operating environment, and the like. Conventionally used resins include polyamide 66, polyamide 46, polyphenylene sulfide, polyether ether ketone and the like reinforced with glass fiber or carbon fiber. Among these resins, polyamide 66 reinforced with glass fiber is most often used because of a balance of appropriate heat resistance, strength characteristics, and cost.

  However, even in a temperature environment where the polyamide 66 is sufficiently usable, the rolling bearing is used in an environment in which the amide bond existing in the chemical structure of the polyamide 66 is affected by an aggressive agent. In some cases, polyphenylene sulfide, polyether ether ketone, or the like, which has better chemical resistance than polyamide 66, is used as a material for the cage. However, since polyphenylene sulfide and polyetheretherketone are expensive, the use of these resins as the material for the cage has led to an increase in the cost of the entire rolling bearing.

  In general, polyamide resins such as polyamide 66 (especially glass fiber reinforced products) are subjected to a humidity conditioning treatment that intentionally contains a certain amount of water for the purpose of improving toughness and suppressing changes in water absorption dimensions. ing. However, moisture absorbed in the polyamide resin is discharged out of the cage due to centrifugal force or temperature rise due to the rotation of the rolling bearing, which may cause a dimensional change and cause some trouble. .

  From such a background, a coating having a gas barrier property is provided on the surface of the resin cage to suppress the entry of external factors such as moisture that causes dimensional changes and oxygen that causes deterioration. Reliable and long-life rolling bearings have been proposed. Examples of the film having a gas barrier property include a film made of an inorganic material such as a diamond-like carbon film and a vapor deposition film of silicon particles, and a film made of an organic material such as a film of ethylene vinyl copolymer or polyvinylidene chloride. It was.

  On the other hand, as a pulley for guiding a belt for driving automobile engine accessories, a resin pulley formed by integrally molding a resin portion on the outer periphery of a rolling bearing has been conventionally employed. This resin pulley requires molding accuracy of the outer periphery of the resin part that guides the belt, strength characteristics that can withstand the tension of the belt, heat resistance to high temperatures due to continuous load use, and calcium chloride resistance (chemical resistance). Is done.

  Therefore, in order to improve the molding accuracy, strength characteristics, heat resistance, and calcium chloride resistance as described above, a reinforced polyamide 66, a reinforced polyamide 610, and a reinforced polyamide containing about 15 to 40% by mass of glass fiber are used as resin materials. 612, or a resin pulley using a composite material of polyphenylene sulfide and mineral, or a polyamide resin such as polyamide 6, polyamide 66, polyamide 11, or polyamide 12 has been proposed (see, for example, Patent Documents 1 and 2).

Patent Document 3 proposes a resin pulley using a polyamide resin composition composed of polyamide 66, polyamide 612, and glass fiber having a good balance of heat resistance, strength characteristics, and calcium chloride resistance. It has become.
Furthermore, Patent Document 4 discloses a polyamide resin composed of polyamide 66, amorphous aromatic polyamide, low water absorption polyamide, and glass fiber, which further improves the balance of heat resistance, strength characteristics, and calcium chloride resistance. Resin pulleys using the composition have been proposed and put into practical use.

  However, since the resin pulley having both heat resistance, strength characteristics, and calcium chloride resistance as described above uses an expensive low water-absorbing polyamide in addition to the polyamide 66, the resin composition is expensive. It was. Moreover, although the calcium chloride resistance has been improved due to the use of a low water-absorbing polyamide, the heat resistance and strength characteristics were lower than those using only the polyamide 66. For this reason, there is a possibility that some trouble may occur in the resin pulley due to long-term use.

  From such a background, a coating having a gas barrier property was provided on the surface of the resin part of the resin pulley to suppress the intrusion of external factors such as moisture that causes dimensional changes and oxygen that causes deterioration, A highly reliable and long-life resin pulley has been proposed. Examples of the film having a gas barrier property include a film made of an inorganic material such as a diamond-like carbon film and a vapor deposition film of silicon particles, and a film made of an organic material such as a film of ethylene vinyl copolymer or polyvinylidene chloride. It was.

Japanese Patent No. 3506735 Japanese Patent No. 2838037 JP 2000-2317 A JP 2007-232106 A JP 2000-346082 A

  However, the coating made of an inorganic material as described above has a very excellent gas barrier property and does not deteriorate the gas barrier property even at a high temperature, but because of its low flexibility, it tends to crack due to thermal expansion, There was a risk of external factors such as moisture and oxygen entering from there. In addition, the coating made of an organic material as described above has high flexibility but low heat resistance. Therefore, although it exhibits excellent gas barrier properties when used at low temperatures, the coating gradually increases at high temperatures. There was a possibility that the gas barrier property would deteriorate due to deterioration.

  Accordingly, the present invention solves the problems of the prior art as described above, and provides a polymer material molded article in which gas such as oxygen and water vapor is less likely to enter and dimensional change and deterioration are less likely to occur, and a method for manufacturing the same. Let it be an issue. It is another object of the present invention to provide a mechanical component with high reliability and long life despite being at least partially made of a polymer material.

In order to solve the above problems, the present invention has the following configuration. That is, the polymer material molded product according to claim 1 of the present invention is a polymer material molded product obtained by molding a polymer material, containing silicon dioxide obtained by converting polysilazane and an acrylic resin, and having a gas barrier property. The surface is coated with an organic-inorganic composite film having
According to a second aspect of the present invention, there is provided a method for producing a molded article of a polymer material comprising a molded article of a polymer material containing silicon dioxide and an acrylic resin and having an organic-inorganic composite film having gas barrier properties on the surface. In the production, a coating agent containing polysilazane and an acrylic resin is disposed on the surface of a polymer material molded product obtained by molding the polymer material, and then the polysilazane is converted into silicon dioxide.

Furthermore, the manufacturing method of the polymeric material molded product of Claim 3 which concerns on this invention is a manufacturing method of the polymeric material molded product of Claim 2, The polysilazane and acrylic resin which are contained in the said coating agent in the manufacturing method of Claim 2. The mass ratio is 95: 5 to 50:50.
Furthermore, the mechanical component of claim 4 according to the present invention is a mechanical component in which at least a part is made of a polymer material, and the portion made of the polymer material is a molded article of the polymer material according to claim 1. It is characterized by being.

Furthermore, the mechanical component of claim 5 according to the present invention is a mechanical component at least part of which is made of a polymer material, and the portion made of the polymer material is the high part of claim 2 or claim 3. It is a polymer material molded product manufactured by a method for manufacturing a molecular material molded product.
Furthermore, the mechanical component of claim 6 according to the present invention is the mechanical component according to claim 4 or 5, which is a rolling bearing, a linear motion guide device, a ball screw, a pulley, or a gear for an electric power steering device. It is characterized by that.

Since the polymer material molded article of the present invention includes an organic-inorganic composite film having gas barrier properties, flexibility and heat resistance that suppress the entry of external factors such as oxygen and water vapor, dimensional change and deterioration occur. Hateful.
In addition, the method for producing a molded article of a polymer material according to the present invention includes a polymer material coated with an organic-inorganic composite film having gas barrier properties, flexibility, and heat resistance that suppresses the entry of external factors such as oxygen and water vapor The molded product can be easily manufactured.

  Furthermore, the mechanical component of the present invention has a gas barrier in which at least a part is made of a polymer material, but the part made of the polymer material suppresses the entry of external factors such as oxygen and water vapor. Since it is covered with an organic-inorganic composite film having properties, flexibility and heat resistance, it can be used at high temperatures and has high reliability and long life.

It is a front view which shows the structure of the resin pulleys which are 1st embodiment of the machine component which concerns on this invention. It is AA sectional drawing of the resin pulleys of FIG. It is a fragmentary longitudinal cross-section which shows the structure of the cylindrical roller bearing which is 2nd embodiment of the machine component which concerns on this invention. It is a perspective view of the holder | retainer integrated in the cylindrical roller bearing of FIG. It is a fragmentary longitudinal cross-section which shows the structure of the angular ball bearing which is a modification of 2nd embodiment. It is a perspective view of the holder | retainer integrated in the angular ball bearing of FIG. It is a longitudinal cross-sectional view which shows the structure of the deep groove ball bearing which is another modification of 2nd embodiment. It is a perspective view of the crown-shaped cage incorporated in the deep groove ball bearing of FIG. It is a figure which shows the structure of the electric power steering apparatus of a motor vehicle. FIG. 10 is a cross-sectional view of a housing portion of the electric power steering device of FIG. 9. It is a perspective view which shows the structure of the reduction gear for electric power steering apparatuses which is 3rd embodiment of the machine component which concerns on this invention.

DESCRIPTION OF EMBODIMENTS Embodiments of a polymer material molded article, a manufacturing method thereof, and a machine part according to the present invention will be described in detail with reference to the drawings.
The polymer material molded article of the present embodiment is a polymer material molded article formed by molding a polymer material, and silicon dioxide obtained by converting polysilazane into at least a part of the surface (preferably the entire surface). And an organic-inorganic composite film containing an acrylic resin and having a gas barrier property. This organic-inorganic composite film may be composed only of silicon dioxide and an acrylic resin, or may contain a compounding agent described later.

  Since the organic / inorganic composite film has a gas barrier property that suppresses the entry of external factors such as oxygen and water vapor, the polymer material molded article coated with the organic / inorganic composite film is deteriorated by oxygen or absorbed by water. Dimensional change hardly occurs. In addition, since the water vapor permeability is low, the amount of water contained in the polymer material molded product is unlikely to decrease. Therefore, a dimensional change due to a change in the amount of moisture hardly occurs. Furthermore, since the organic-inorganic composite film is excellent in resistance to various chemicals such as a snow melting agent (calcium chloride), the polymer material molded article coated with the organic-inorganic composite film is less prone to problems caused by the chemical.

  Furthermore, since the organic-inorganic composite film has flexibility, the organic-inorganic composite film is hardly damaged and the gas barrier property is hardly reduced. Therefore, the polymer material molded article coated with the organic-inorganic composite film maintains excellent gas barrier properties over a long period of time. Furthermore, since the organic / inorganic composite film has heat resistance, the polymer material molded product coated with the organic / inorganic composite film is less likely to deteriorate even when used at high temperatures, resulting in a decrease in gas barrier properties. Is unlikely to occur.

In addition, when the organic-inorganic composite film is composed only of silicon dioxide, it is not flexible due to its brittleness and easily cracks. However, since the organic-inorganic composite film contains an acrylic resin, the acrylic resin Since it plays the role of a binder, it becomes easy to form an organic-inorganic composite film that is tough and hardly cracks.
Here, the organic-inorganic composite film will be described in more detail. First, polysilazane will be described. Polysilazane is an inorganic polymer that does not contain organic components such as carbon and is composed only of silicon, nitrogen, and hydrogen. — (SiH ₂ NH) — (wherein all or part of H is an alkyl group, phenyl And a repeating unit that may be substituted with a substituent such as a group. Polysilazane is a ceramic precursor that is converted into silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ) or the like by heat treatment in the atmosphere or humidification treatment at room temperature.

  Examples of polysilazanes include those disclosed in JP-A-7-305029 and JP-A-2000-073012. In the present invention, known or commercially available polysilazanes can be used without problems. Examples of the polysilazane include chain polysilazane and cyclic polysilazane. Examples of the chain polysilazane include polyorganosilazanes such as perhydropolysilazane, polymethylhydrosilazane, polyN-methylsilazane, polyN- (triethylsilyl) allylsilazane, polyN- (dimethylamino) cyclohexylsilazane, and phenylpolysilazane. Can be given.

  These polysilazanes may be used individually by 1 type, and may use 2 or more types together. Of these, perhydropolysilazane, polymethylhydrosilazane, polyN-methylsilazane, and phenylpolysilazane are preferred because of their excellent corrosion resistance. Examples of commercially available polysilazanes include “NAX120”, “NP110”, and “NL110A” manufactured by AZ Electronic Materials Co., Ltd.

  Next, the acrylic resin will be described. Examples of the acrylic resin include those disclosed in JP-A-7-305029, and known or commercially available acrylic resins can be used without any problem in the present invention. Specific examples of acrylic resins include acrylic acid esters (as alcohol residues, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, Cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.); methacrylic acid ester (alcohol residue is the same as above); 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2 -Hydroxy group-containing monomers such as hydroxypropyl methacrylate; acrylamide, methacrylamide, N-methyl methacrylamide, N-methyl acrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylate Amide group-containing monomers such as luamide and N-phenylacrylamide; Amino group-containing monomers such as N, N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate; Epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether Monomers containing sulfonic acid groups or salts thereof such as styrene sulfonic acid, vinyl sulfonic acid, and salts thereof (for example, sodium salt, potassium salt, ammonium salt, etc.); crotonic acid, itaconic acid, acrylic acid, maleic acid, Monomer containing a carboxyl group such as fumaric acid and salts thereof (for example, sodium salt, potassium salt, ammonium salt, etc.) or a salt thereof; monomer containing acid anhydride such as maleic anhydride, itaconic anhydride; Vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleic acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, vinyl chloride, etc. The thing made from the combination of a mer is illustrated. Examples of commercially available acrylic resins include “BR101” and “BR102” manufactured by AZ Electronic Materials Co., Ltd.

  The thickness of the organic-inorganic composite film is not particularly limited, but is preferably 0.2 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. If the thickness of the organic-inorganic composite film is 0.2 μm or more, the organic-inorganic composite film can be provided uniformly regardless of the surface roughness of the surface of the polymer material molded article covered with the organic-inorganic composite film. The occurrence of film defects can be suppressed. Moreover, if the thickness of the organic-inorganic composite film is 10 μm or less, cracks are unlikely to occur and film formation becomes easy.

On the other hand, the type of polymer material constituting the polymer material molded product is not particularly limited, and examples thereof include polyamide resin, polyphenylene sulfide, and polyether ether ketone. However, considering the cost of the polymer material molded product, a polyamide resin is preferable. Examples of the polyamide resin include aliphatic polyamide resins such as polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 66, polyamide 610, and polyamide 612, and aromatic polyamide resins such as modified polyamide 6T and polyamide 9T. Among these polyamide resins, relatively inexpensive polyamide 66 and polyamide 46 are used.
Is more preferable. These polymer materials may be used alone or in combination of two or more.

  Moreover, you may use the resin composition which consists of resin and a fiber reinforcement as a polymeric material. Then, the heat resistance and strength characteristics of the polymer material are excellent. Examples of the fiber reinforcing material include glass fiber and carbon fiber. A polyamide resin reinforced with glass fiber (particularly polyamide 66) is most suitable because it has excellent heat resistance and strength properties and is inexpensive. Further, the polymer material may be blended with various additives such as a lubricant, a heat stabilizer, an antioxidant, a thermal conductivity improver, and a plasticizer.

A method for molding such a polymer material is not particularly limited, and a conventional resin molding method can be employed without any problem. Examples thereof include a melt molding method such as an injection molding method, a molding method by machining, and a sintering molding method.
A polymer material molded article coated with such an organic-inorganic composite film is less prone to problems such as dimensional changes and deterioration due to oxygen and chemicals. Therefore, it is suitable as a member constituting a machine part such as a rolling bearing. A member made of a polymer material is prone to the above-mentioned problems as compared with a metal member, and thus tends to reduce the reliability and life of machine parts. The component is reliable and has a long life despite being at least partially composed of a polymeric material.

Mechanical parts to which the polymer material molded product of the present embodiment can be applied are not particularly limited, and examples thereof include a rolling bearing, a linear motion guide device, a ball screw, a pulley, or a gear for an electric power steering device. It is done.
Next, the manufacturing method of the polymeric material molded article of this embodiment provided with an organic inorganic composite film is demonstrated. First, a coating agent containing polysilazane and an acrylic resin is coated to a uniform thickness on the surface of a polymer material molded product formed by molding a polymer material. The coating method is not particularly limited, but if it is a liquid coating agent, for example, spray coating, air doctor coating, blade coating, dip coating, electrodeposition coating, etc., in addition to application by brush etc. . Coating by such a method may be performed once or a plurality of times, and the thickness of the coating agent may be controlled so that the thickness of the organic-inorganic composite film becomes a desired value.

  When the polymer material molded article coated with the coating agent was subjected to a treatment for converting polysilazane to silicon dioxide, the organic-inorganic composite film containing silicon dioxide and acrylic resin and having gas barrier properties was coated. A polymer material molded product is obtained. An example of the treatment for converting polysilazane to silicon dioxide is a treatment in which the polysilazane is left in the atmosphere at room temperature for 2 weeks. By this treatment, polysilazane is converted to silicon dioxide and crystallization proceeds, and an organic-inorganic composite film having sufficient gas barrier properties is formed.

However, since the treatment at room temperature requires a long time for crystallization, a treatment that is allowed to stand under heating is preferable. Heating can accelerate the crystallization rate. For example, the heating temperature is preferably 50 ° C. or higher and 220 ° C. or lower, and more preferably 80 ° C. or higher and 170 ° C. or lower. The heating time is preferably 30 minutes or longer and 120 minutes or shorter.
In addition, it is preferable that all the polysilazane is converted into silicon dioxide because the above-mentioned various properties of the organic-inorganic composite film are excellent. However, some of the polysilazane is not converted into silicon dioxide, and the organic-inorganic composite film. It may exist as polysilazane.

  The mass ratio of polysilazane and acrylic resin contained in the coating agent is preferably 95: 5 to 50:50. When the proportion of polysilazane is less than 50% by mass, the content of silicon dioxide in the organic-inorganic composite film decreases, and thus the gas barrier property of the organic-inorganic composite film may be insufficient. On the other hand, when the ratio of polysilazane is more than 95% by mass, the content of the acrylic resin in the organic-inorganic composite film decreases, and the flexibility of the organic-inorganic composite film may be insufficient. As a result, cracks may occur in the organic-inorganic composite film due to the thermal expansion of the polymer material molded article, and the gas barrier property may be reduced. In order to make such inconvenience less likely to occur, the mass ratio of polysilazane and acrylic resin is more preferably 95: 5 to 80:20.

  As the coating agent, a coating solution in which polysilazane and an acrylic resin are dissolved in a solvent is preferable. When the coating liquid is used, it is necessary to convert polysilazane to silicon dioxide and to remove (dry) the solvent by evaporating it. The drying method is not particularly limited as long as it can remove the solvent in the coating liquid coated on the surface of the polymer material molded article, but it should be placed in an environment such as heating, decompression, and air flow. Can be dried.

  The type of solvent is not particularly limited as long as it does not react with polysilazane and can dissolve polysilazane. For example, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; pentane, hexane, isohexane Aliphatic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane; methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, aliphatic hydrocarbons such as methylpentane, heptane, isohebutane, octane, and isooctane; Halogenated hydrocarbons such as ethylidene chloride and trichloroethane; ethers such as ethyl ether, dioxyethane, dimethyldioxane, tetrahydrofuran and tetrahydropyran. These solvents may be used alone or in combination of two or more.

  The concentration of the solute (polysilazane and acrylic resin) in the coating liquid is not particularly limited. However, in consideration of the operability of the process of coating the coating liquid on the surface of the polymer material molded article, it is 5% by mass or more and 20% by mass. The following is preferred. Moreover, since the thickness of the organic-inorganic composite film is determined by this concentration, if it is less than 5% by mass, the thickness of the organic-inorganic composite film becomes thin, and the gas barrier property may be insufficient. On the other hand, if it exceeds 20% by mass, the solute tends to aggregate and whitening tends to occur.

  Moreover, you may mix the catalyst which accelerates | stimulates the conversion reaction of polysilazane to silicon dioxide with the coating liquid as needed. Examples of the catalyst include palladium, an amine compound, and a mixture of an amine compound and silver particles. In addition, as for the combination of the catalyst and the solvent used in the coating liquid, any combination of the catalyst and the solvent described above can form the organic-inorganic composite film without any problem. However, the combination of an amine compound and xylene is most preferable because the conversion reaction can be completed in a temperature of 200 ° C. or less and in a short time, and the polymer material molded article is hardly adversely affected.

  Furthermore, you may mix a compounding agent with a coating liquid as needed. Examples of the compounding agent include inorganic materials such as talc, calcium carbonate, and kaolin, oil-soluble organic dyes such as anthraquinone compounds, and carbon black. The addition amount of the compounding agent is preferably 0.05% by mass or more and 30% by mass or less, and more preferably 1% by mass or more and 5% by mass or less of the entire coating liquid.

  Furthermore, it is preferable to subject the surface of the polymer material molded article to a treatment for improving the adhesion of the organic-inorganic composite film to the surface to be coated before coating the coating liquid. This treatment includes known surface activation treatments such as corona discharge treatment, plasma activation treatment, glow discharge treatment, reverse sputtering treatment, roughening treatment, ethyleneimine, amine, epoxy, urethane, polyester. Primer treatment using a primer agent such as a system may be mentioned.

Hereinafter, an embodiment of a machine part to which the polymer material molded article of the present embodiment is applied will be described.
[First embodiment of machine parts]
FIG. 1 is a front view showing a structure of a resin pulley that is an embodiment of a mechanical component according to the present invention, and FIG. 2 is a cross-sectional view taken along line AA of the resin pulley of FIG.
The resin pulley 10 according to this embodiment includes a rolling bearing 11 and a resin portion 12. The rolling bearing 11 holds the rolling element 3 between the inner ring 1, the outer ring 2, a plurality of rolling elements 3 that are arranged to freely roll between the two wheels 1 and 2, and the two wheels 1 and 2. A cage 4 and sealing devices 5 and 5 covering the opening between the wheels 1 and 2 are provided. Note that the cage 4 and the seal device 5 may not be provided. Further, the sealing device 5 may be a contact rubber seal as shown in FIG. 2 or a non-contact seal such as a shield.

  The resin portion 12 is formed by injection molding of a polymer material and is integrally attached to the outer peripheral surface of the outer ring 2 of the rolling bearing 11 (the polymer portion 12 is a constituent material of the present invention). Equivalent to a molded product). Specifically, the resin portion 12 includes an inner diameter side cylindrical portion 12a into which the outer ring 2 of the rolling bearing 11 is fitted, an outer diameter side cylindrical portion 12b, and a disc portion 12c that connects both the cylindrical portions 12a and 12b. , And a plurality of ribs 12 d formed radially to reinforce the resin portion 12. The outer peripheral surface 12e of the outer diameter side cylindrical portion 12b forms a belt guide surface of a driving belt (not shown). A concave groove for preventing the resin part 12 from being attached and detached is formed on the outer peripheral surface of the outer ring 2.

  The type of the polymer material constituting the resin portion 12 is not particularly limited, but in the resin pulley, in order to reduce the noise by suppressing the occurrence of vibration due to the vibration of the belt during driving, The roundness (unevenness) of the outer peripheral surface 12e of the outer cylindrical portion 12b that guides the belt is required to be good, and the mechanical strength and heat resistance to withstand the belt tension are required to be good. It is done. Therefore, as the polymer material constituting the resin portion 12, fillers such as glass fibers and carbon fibers and various additives (lubricants, thermal stabilizers, antioxidants, thermal conductivity improvers, plasticizers, etc.) are used. A resin composition blended with the resin is preferred.

  Examples of preferred resins include polyamide resins, polyphenylene sulfide, and polyether ether ketone. Examples of the polyamide resin include aliphatic polyamide resins such as polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 66, polyamide 610, and polyamide 612, and aromatic polyamide resins such as modified polyamide 6T and polyamide 9T.

  Judging from the balance of cost, heat resistance, and strength characteristics of the resin composition, the resin composition using polyamide 66, which is excellent in heat resistance and fatigue resistance, as a base resin and glass fiber as a reinforcing material is most preferable. The blending amount of the glass fiber is preferably 25% by mass or more and 55% by mass or less of the entire resin composition. When the blending amount of the glass fiber is less than 25% by mass, the heat resistance and strength characteristics of the resin composition may be insufficient. On the other hand, if it exceeds 55% by mass, the melt viscosity of the resin composition becomes high and the moldability may be insufficient.

  The molecular weight of polyamide 66 is preferably 13,000 to 30000 in terms of number average molecular weight in view of injection moldability, and more preferably 18000 to 26000 in terms of number average molecular weight in consideration of fatigue resistance and high molding accuracy. If the number average molecular weight of the polyamide 66 is less than 13000, the molecular weight is too low, resulting in low fatigue resistance and low practicality. On the other hand, if the number average molecular weight of the polyamide 66 is more than 30000, the fatigue resistance is excellent, but the glass fiber is contained in an amount of 25% by mass or more to achieve mechanical strength such as impact strength required for the resin pulley. When the content is less than or equal to mass%, the melt viscosity of the resin composition becomes high, and it becomes difficult to manufacture the resin portion 12 with high accuracy by an injection molding method.

An organic-inorganic composite film (not shown) having flexibility and heat resistance on the surface of the resin portion 12 of the resin pulley 10 in addition to the gas barrier property that suppresses the entry of external factors such as oxygen and water vapor. ) Is coated. The organic / inorganic composite film is most preferably coated on the entire surface of the resin portion 12, but may be coated on a part of the surface of the resin portion 12.
Since the resin pulley 10 of this embodiment is provided with an organic-inorganic composite film on the surface of the resin portion 12, it has excellent resistance to various chemicals (for example, calcium chloride). For this reason, even if a polyamide resin such as polyamide 66, which is slightly inferior in chemical resistance, is used as the base resin of the resin composition constituting the resin portion 12, the resin portion 12 is not easily affected by the chemical. Accordingly, for example, problems caused by the snow melting agent (calcium chloride) are suppressed, so the resin pulley 10 of the present embodiment has a high reliability and a long life.

In addition, a resin composition in which a polyamide resin such as polyamide 66 is reinforced with a fiber reinforcing material has excellent molding accuracy, strength characteristics, and heat resistance, and is relatively inexpensive. Therefore, the base of the resin composition constituting the resin portion 12 is used. If a polyamide resin such as polyamide 66 is used as the resin, the resin pulley 10 of the present embodiment is inexpensive, highly reliable, and has a long life.
Furthermore, since the organic-inorganic composite film has a gas barrier property, it is possible to block a gas such as oxygen that causes deterioration of the resin. In addition, since the organic-inorganic composite film also has a water vapor barrier property, it is difficult for water vapor to pass therethrough and can block water (water vapor). Therefore, since the occurrence of the malfunction of the resin pulley 10 due to the deterioration of the resin portion 12 and the dimensional change due to water absorption is suppressed, the resin pulley 10 of the present embodiment has a high reliability and a long life.

Such a resin pulley 10 can be suitably used as, for example, a driving belt for engine accessories mounted on an automobile, a tensioner pulley for other belts, or an idler pulley.
This first embodiment shows an example of the present invention, and the present invention is not limited to this embodiment. For example, in the present embodiment, a deep groove ball bearing has been described as an example of a rolling bearing, but the present invention can be applied to various types of rolling bearings. For example, radial rolling bearings such as angular contact ball bearings, self-aligning ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, and self-aligning roller bearings, and thrust types such as thrust ball bearings and thrust roller bearings This is a rolling bearing.

  Further, the type of rubber used for the contact rubber seal of the rolling bearing 11 is not particularly limited, but nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, or the like is used as a raw rubber, and various fillers are blended therein. Can be used. Further, the type of lubricant filled in the rolling bearing 11 is not particularly limited, and general lubricating oil or grease can be used. A grease in which α-olefin oil, alkyldiphenyl ether oil or the like is used as a base oil, diurea or the like is used as a thickener, and additives for lubricants such as antioxidants and antiwear agents are blended is preferable.

[Example of the first embodiment]
The surface of the resin part of a resin pulley having a configuration substantially similar to that of the resin pulley of FIG. 1 was prepared, and the calcium chloride resistance was evaluated.
The resin pulley is formed by integrally forming a resin portion on the outer periphery of the outer ring of the deep groove ball bearing by insert molding using the deep groove ball bearing of the reference number 6203DDL18 as a core. This deep groove ball bearing has a contact rubber seal and a concave groove on the outer peripheral surface of the outer ring. Moreover, the polymer material which comprises a resin part is the polyamide 66 (UBE nylon 2020GU6 by Ube Industries, Ltd.) which contains 30 mass% of glass fiber, and contains the copper iodide type | system | group heat stabilizer. The number average molecular weight of the polyamide 66 is 20000.

  The coating liquid for forming the film was prepared as follows. Perhydropolysilazane (“NAX120” manufactured by AZ Electronic Materials Co., Ltd.) was dissolved in xylene to prepare each polysilazane solution having a concentration of 5, 10, 15, and 20% by mass. In addition, an acrylic resin (“BR101” manufactured by AZ Electronic Materials Co., Ltd.) was dissolved in xylene to prepare an acrylic resin solution having a concentration of 20% by mass. And each polysilazane solution and acrylic resin solution were mixed in the ratio (mass ratio) of 10: 0, 9: 1, and 7: 3, and each mixed solution was obtained.

  The resin part of the resin pulley was immersed in these mixed solutions, respectively, and the mixed solution was uniformly coated on the surface of the resin part of the resin pulley. Heat treatment was performed at 170 ° C. for 1 hour to evaporate xylene and convert polysilazane to silicon dioxide. Thereafter, the film was allowed to stand for 2 weeks at room temperature in the atmosphere to be completely cured to form a film. And the resin pulley was manufactured using the resin part which formed the film in this way. A resin pulley having the same configuration as that of the resin pulley except that the coating film was not provided was also manufactured. And about these resin pulleys, the calcium chloride resistance was evaluated. The test method is as follows.

  First, the resin pulley was immersed in hot water at 80 ° C. for 2 hours to absorb water, and then immersed in an aqueous calcium chloride solution having a concentration of 50% by mass for 5 minutes. Next, in a state where a radial load of 1470 N was applied, the resin pulley was left in the thermostat and the temperature in the thermostat was changed as follows. That is, the temperature was raised from 20 ° C. to 110 ° C. over 30 minutes, held at 110 ° C. for 2 hours, further lowered to 20 ° C. over 30 minutes, and then held at 20 ° C. for 1 hour.

  Then, the temperature change was repeated as one cycle, and the resin pulley was immersed in the calcium chloride aqueous solution for 5 minutes every two cycles. The test was conducted up to 10 cycles while checking the occurrence of cracks in the resin portion every 2 cycles. The results are shown in Table 1.

  As a result, the resin pulley provided with the coating did not crack in the resin part in two cycles, whereas the resin pulley not provided with the coating cracked in two cycles. From this result, it can be seen that the formation of the coating on the surface of the resin part blocked the ingress of moisture (calcium chloride aqueous solution) into the resin part, thereby improving the calcium chloride resistance.

  Moreover, when the acrylic resin was not contained in the said film, ie, when the film which consists only of silicon dioxide was provided, the crack generate | occur | produced at an early stage, so that the polysilazane density | concentration of a polysilazane solution was high. This is presumably because the higher the polysilazane concentration, the thicker the coating, and the coating cannot follow the thermal expansion of the resin portion, causing fine cracks in the coating, from which the calcium chloride aqueous solution entered.

  However, when the coating contains an acrylic resin, that is, when an organic-inorganic composite film made of silicon dioxide and an acrylic resin is provided, the organic-inorganic composite film has flexibility, so The organic / inorganic composite film follows the expansion and is less likely to crack. Therefore, it is considered that the penetration of the aqueous calcium chloride solution was blocked and the calcium chloride resistance was improved.

[Second Embodiment of Machine Parts]
FIG. 3 is a partial longitudinal sectional view showing a structure of a cylindrical roller bearing which is another embodiment of the mechanical component according to the present invention, and FIG. 4 is a perspective view of a cage incorporated in the cylindrical roller bearing of FIG. is there.
The cylindrical roller bearing 20 of the second embodiment includes an inner ring 21 having a raceway surface, an outer ring 22 having a raceway surface facing the raceway surface of the inner ring 21, and a plurality of rolls disposed between the raceway surfaces. A rolling element (cylindrical roller) 23 and a resin cage 24 that holds the rolling element 23 between the inner ring 21 and the outer ring 22 are provided. The cage 24 is an outer ring guide type cage that is guided by an inner diameter surface 22 a (cage guide surface) of the outer ring 22. Although not shown, a sealing device such as a rubber seal or a shield may be provided. Further, a lubricant such as lubricating oil or grease may be disposed in the bearing inner space formed between the inner ring 21 and the outer ring 22.

  The cage 24 is formed by injection molding of a polymer material (the cage 24 corresponds to a polymer material molded product that is a constituent of the present invention). The type of the polymer material constituting the cage 24 is not particularly limited, but the cage is required to have good dimensional accuracy and have good mechanical strength and heat resistance. Desired. Therefore, as the polymer material constituting the cage 24, fillers such as glass fibers and carbon fibers and various additives (lubricants, thermal stabilizers, antioxidants, thermal conductivity improvers, plasticizers, etc.) are used. The resin composition mix | blended with resin is preferable.

  Examples of preferred resins include polyamide resins, polyphenylene sulfide, and polyether ether ketone. Examples of the polyamide resin include aliphatic polyamide resins such as polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 66, polyamide 610, and polyamide 612, and aromatic polyamide resins such as modified polyamide 6T and polyamide 9T.

The surface of the cage 24 is coated with an organic-inorganic composite film (not shown) having flexibility and heat resistance in addition to gas barrier properties that suppress the entry of external factors such as oxygen and water vapor. Yes. The organic / inorganic composite film is most preferably coated on the entire surface of the cage 24, but may be coated on a part of the surface of the cage 24.
Since the cylindrical roller bearing 20 of this embodiment is provided with the organic-inorganic composite film on the surface of the cage 24, it has excellent resistance to various chemicals (for example, calcium chloride). For this reason, even when a polyamide resin such as polyamide 66, which is slightly inferior in chemical resistance, is used as the base resin of the resin composition constituting the cage 24, the cage 24 is hardly affected by the chemical. Therefore, for example, since problems caused by the snow melting agent (calcium chloride) are suppressed, the cylindrical roller bearing 20 of the present embodiment has a high reliability and a long life.

In addition, since a resin composition obtained by reinforcing a polyamide resin such as polyamide 66 with a fiber reinforcing material has excellent molding accuracy, strength characteristics, and heat resistance and is relatively inexpensive, the base of the resin composition constituting the cage 24. If a polyamide resin such as polyamide 66 is used as the resin, the cylindrical roller bearing 20 of this embodiment is inexpensive, highly reliable, and has a long life.
Furthermore, since the organic-inorganic composite film has a gas barrier property, it is possible to block a gas such as oxygen that causes deterioration of the resin. In addition, since the organic-inorganic composite film also has a water vapor barrier property, it is difficult for water vapor to pass therethrough and can block water (water vapor). Therefore, since the occurrence of defects in the cylindrical roller bearing 20 due to the deterioration of the cage 24 and the dimensional change due to water absorption is suppressed, the cylindrical roller bearing 20 of the present embodiment has a high reliability and a long life.

  The second embodiment shows an example of the present invention, and the present invention is not limited to the present embodiment. For example, in this embodiment, a cylindrical roller bearing has been described as an example of a rolling bearing, but the present invention can be applied to various types of rolling bearings. For example, radial rolling bearings such as deep groove ball bearings, angular contact ball bearings, self-aligning ball bearings, tapered roller bearings, needle roller bearings, and self-aligning roller bearings, and thrust types such as thrust ball bearings and thrust roller bearings This is a rolling bearing.

  FIG. 5 is a partial longitudinal sectional view showing the structure of an angular ball bearing which is a modification of the second embodiment, and FIG. 6 is a perspective view of a cage incorporated in the angular ball bearing of FIG. 7 is a longitudinal sectional view showing the structure of a deep groove ball bearing which is another modified example of the second embodiment, and FIG. 8 is a perspective view of a crown-shaped cage incorporated in the deep groove ball bearing of FIG. It is. Since the structure of these angular ball bearings and deep groove ball bearings is substantially the same as the cylindrical roller bearing 20 of the second embodiment, description thereof is omitted. 5 to 8, the same or corresponding parts as those in FIGS. 3 and 4 are denoted by the same reference numerals as those in FIGS.

[Example of the second embodiment]
What formed the organic-inorganic composite film | membrane on the surface of the resin-made crown-shaped holder | retainer of the structure substantially the same as the holder | retainer of FIG.
The crown-shaped cage used for the evaluation is a cage incorporated in a deep groove ball bearing having a nominal number 6203, which is formed by injection molding of a polymer material. The polymer material constituting the crown-shaped cage is polyamide 66 (Ultramid A3HG5 manufactured by BASF) containing 25% by mass of glass fiber, and contains an amine-based antioxidant.

  The coating liquid for forming the film was prepared as follows. Perhydropolysilazane (“NP110” manufactured by AZ Electronic Materials Co., Ltd.) was dissolved in xylene to prepare each polysilazane solution having a concentration of 5, 10, 15, and 20% by mass. In addition, an acrylic resin (“BR101” manufactured by AZ Electronic Materials Co., Ltd.) was dissolved in xylene to prepare an acrylic resin solution having a concentration of 20% by mass. And each polysilazane solution and acrylic resin solution were mixed in the ratio (mass ratio) of 10: 0, 9: 1, 7: 3, 5: 5, and each mixed solution was obtained.

  Resin cages were respectively immersed in these mixed solutions, and the mixed solution was uniformly coated on the surface of the resin cage. Heat treatment was performed at 150 ° C. for 1 hour to evaporate xylene and convert polysilazane to silicon dioxide. Thereafter, the film was allowed to stand for 2 weeks at room temperature in the atmosphere to be completely cured to form a film. Also, a resin cage having the same configuration as the resin cage was prepared except that the coating film was not provided. And about these resin cages, water vapor | steam barrier property was evaluated. The test method is as follows.

  First, a resin cage was held in a vacuum thermostat at 80 ° C. for 1 week to make it completely dry. Then, the mass of the completely dry resin cage was measured. Next, this absolutely dry resin cage was held in a high-temperature and high-humidity tank having a temperature of 80 ° C. and a relative humidity of 80% for one week to absorb moisture. And the mass of the resin cage made to absorb moisture was measured, and the moisture absorption rate was calculated by the following formula. The unit of mass in the following formula is g.

            Moisture absorption rate (%) = (mass after moisture absorption−absolute dry mass) / absolute dry mass × 100

The results are shown in Table 2. In addition, the numerical value of the moisture absorption shown in Table 2 is a relative value when the moisture absorption of a resin cage not provided with the coating film is 100.
As can be seen from Table 2, the coating film contains an acrylic resin (i.e., silicon dioxide) as compared to the case where the coating film does not contain an acrylic resin (i.e., the case where the coating film comprises only silicon dioxide). And the organic-inorganic composite film made of an acrylic resin) had a lower moisture absorption rate. From these results, it can be seen that the barrier property against external and internal water vapor is excellent by forming the organic-inorganic composite film on the surface of the resin cage. That is, the organic-inorganic composite film suppressed the absorption of water vapor outside and suppressed the discharge of moisture absorbed inside to the outside.

[Third embodiment of machine parts]
FIG. 9 is a diagram showing a configuration of an electric power steering apparatus for an automobile, and FIG. 10 is a cross-sectional view of a housing portion of the electric power steering apparatus of FIG. FIG. 11 is a perspective view showing the structure of a reduction gear (worm wheel and worm) for an electric power steering apparatus which is an embodiment of the mechanical component according to the present invention.

  The electric power steering device 70 for an automobile incorporates a reduction gear (worm wheel 81 and worm 82) for an electric power steering device as shown in FIG. 11 in order to transmit the output of the electric motor for generating the steering assist output to the steering shaft. ing. The worm wheel 81 and the worm 82 provided in the housing 71 of the electric power steering device 70 have a function of transmitting the rotational driving force of the electric motor 73 generated along with the rotation of the input shaft 72 to the output shaft 74. ing.

  The worm wheel 81 and the worm 82 are made of polyamide 66 (UBE Nylon 1015GU6 manufactured by Ube Industries, Ltd.) reinforced with a polymer material, for example, glass fiber (content is 30% by mass) (worm wheel 81 and The worm 82 corresponds to a polymer material molded product which is a constituent element of the present invention). The surfaces of the worm wheel 81 and the worm 82 are covered with an organic-inorganic composite film (not shown) having flexibility and heat resistance in addition to a gas barrier property that suppresses the entry of external factors such as oxygen and water vapor. Has been. The organic / inorganic composite film is most preferably coated on the entire surfaces of the worm wheel 81 and the worm 82, but may be coated on a part of the surfaces of the worm wheel 81 and the worm 82.

  The electric power steering apparatus 70 according to the present embodiment is excellent in resistance to various chemicals (for example, calcium chloride) since the organic-inorganic composite film is provided on the surfaces of the worm wheel 81 and the worm 82. For this reason, even if a polyamide resin such as polyamide 66, which is slightly inferior in chemical resistance, is used as the base resin of the resin composition constituting the worm wheel 81 and the worm 82, the worm wheel 81 and the worm 82 are not easily affected by the chemical. Therefore, for example, problems caused by the snow melting agent (calcium chloride) are suppressed, so that the electric power steering device 70 of the present embodiment has a high reliability and a long life.

  In addition, a resin composition in which a polyamide resin such as polyamide 66 is reinforced with a fiber reinforcing material has excellent molding accuracy, strength characteristics, and heat resistance, and is relatively inexpensive. Therefore, the resin composition constituting the worm wheel 81 and the worm 82. If a polyamide resin such as polyamide 66 is used as the base resin of the product, the electric power steering device 70 of this embodiment is inexpensive, highly reliable, and has a long life.

  Furthermore, since the organic-inorganic composite film has a gas barrier property, it is possible to block a gas such as oxygen that causes deterioration of the resin. In addition, since the organic-inorganic composite film also has a water vapor barrier property, it is difficult for water vapor to pass therethrough and can block water (water vapor). Therefore, since the occurrence of problems in the electric power steering apparatus 70 due to deterioration of the worm wheel 81 and the worm 82 and dimensional changes due to water absorption is suppressed, the electric power steering apparatus 70 of the present embodiment has a high reliability and a long life. is there.

  The first to third embodiments described above show examples of the present invention, and the present invention is not limited to the above-described embodiments. In the first to third embodiments, resin pulleys, cylindrical roller bearings, and reduction gears for electric power steering devices have been described as examples of machine parts. However, the present invention is applied to other various machine parts. Can be applied. For example, a rolling device such as a ball screw or a linear motion bearing.

DESCRIPTION OF SYMBOLS 10 Resin pulley 11 Rolling bearing 12 Resin part 20 Cylindrical roller bearing 24 Cage 70 Electric power steering apparatus 81 Worm wheel 82 Worm

Claims (6)

  In a polymer material molded product formed by molding a polymer material, the surface is coated with an organic-inorganic composite film containing silicon dioxide obtained by converting polysilazane and an acrylic resin and having gas barrier properties. Molecular material molded product. In producing a polymer material molded article containing an organic-inorganic composite film containing silicon dioxide and an acrylic resin and having a gas barrier property on the surface,
A polymer material molded article comprising a coating material containing polysilazane and an acrylic resin on a surface of a polymer material molded article formed by molding the polymer material, and then converting the polysilazane into silicon dioxide. Manufacturing method.   The method for producing a polymer material molded article according to claim 2, wherein the mass ratio of polysilazane and acrylic resin contained in the coating agent is 95: 5 to 50:50.   2. A machine part comprising at least a part made of a polymer material, wherein the part made of the polymer material is the polymer material molded article according to claim 1.   4. A polymer material produced by the method for producing a molded article of a polymer material according to claim 2 or claim 3, wherein at least a part of the machine component is made of a polymer material. A machine part characterized by being a molded product.   The mechanical component according to claim 4 or 5, wherein the mechanical component is a rolling bearing, a linear motion guide device, a ball screw, a pulley, or a gear for an electric power steering device.

Images